Operating mechanism for discharge lamps



P 1942- A.- G. MUELLER arm. I 2,296,115

OPERATING MECHANISM FOR DISCHARGE LAMPS I Filed .July 11, 1941 2 SheetsSheet 1 lnventons: Adolf G. Mue'l ler,

John M. DisCe Their Attorney.

Sept. 15, 1942. V Gr MUELLER ETAL- 2,296,115

OPERATING MECHANISM FOR DISCHARGE LAMPS Inventors: Adolf G. Mueller,

- J hn M Piscey,

by Fwd MAM Their Attorney.

Patented Sept. 15,1942

UNITED;

STATES PATENT osFIcE orraa'rmc Mscr'mmsMron niscnaacs v rams Adolf G. Mueller and John M. ram, Fairiield,

Conn, assignors to General Electric Company, a corporation of New York I Application July 11-, 1941, Serial No. 401,934 8 Claims. (Cl. 200-41) Our invention relates to an operating mechanism fortubular discharge lamps and more particularly to a starting arrangement for fluorescent lamps.

Fluorescent lamps of the type now in commercial use are provided with a starting switch which, in most instances. is mounted on the associated lamp socket so that the switch is readily accessible for replacement. Starting switches are employed to provide a means for automatically controlling the heating of the lamp cathodes in order to light the lamp. To this end, the switch closes a circuit through the cathodes for a predetermined time interval, for example,

on the order of one to four seconds, to permit heating of the cathodes and thereafter opens the circuit causing a glow discharge to take place between the cathodes, lighting the lamp. Several forms of starting switches are now on the market. Some starting switches utilize an electric discharge device and are known to the trade as glowswitches. .An example of such a glow switch is shown in Patent 2,280,550 issued on April 21, 1942to Wayne C. Smitley, and assigned to the same assignee as the instant application.

Other types of switches utilize a heating resistance operating a bimetallic strip to open and close circuit controlling contacts. A switch of this type is shown in Patent No. 1,951,112 issued to Giinter Wels on March 13, 1934, and assigned capable of accommodating starting switches oi. -various types.

It is another object of our invention to provide an operating mechanism ior fluorescent lamps in which provision is made for connecting various types of starting switches into the operating circuit of the mechanism without the necessity of changing the wiringconnection's i the circuit.

In the accompanying drawings, Fig, 1 is a view or a fluorescent lamp mounted in a lamp holder provided with a starter socket constructed according to our invention; Fig. 2 is a front view of the combined lamp holder-and starter socket; Fig. 3 is a plan view of the device-shown by Fig.

2 Fig. 4 is a view of the interior of the starter socket with the cover plate removed; Fig. 5 is an' I socket showing the starter of Fig. 9 in mounted to the same assignee as the instant application. I

Since the types of switches aforementioned operate on somewhat different principles, provision must be made for connecting these switches into the operating circuit for the fluorescent lamp in various ways. For example, a glow switch is mounted directly in parallel across the cathodes of the lamp while a resistance heater operated switch of the type referred to is connected in the lead line of the current supply as well as across the lamp filaments. This means that it has been necessary in the past to provide separate types of sockets for mounting the various forms of starting switches, the sockets varying according to the number of contact members which it is necessary to connect to thestarting-switch and lamp circuit. We propose to overcome the necessity of providing a'separate socket ioreach type of switch by providing a new and improved socket which is adapted to accommodate: either of the types of starting switch aforementioned.

It is an object of our invention to provide a new and improved socket for starting switches position, and Fig, 11 is a circuit diagram showing an arrangement for operating the lamp using the starter of Fig. 9. v

' Referring to the drawings, we have shown a fluorescent lamp 10- mounted at each end in laii p holders II and II which, in turn, are mounted on a support or reflecting surface 13 by meansv of mounting brackets l4 secured to. the

reflector by screws l5. 'Thelamp holders here in illustrated are of the type'disclosedin Reissue Patent 21,545 issued to Anthony J. Marshaus on August 27, 1940, and assigned to the same assignee as the instant application. It should be manifest, however, that other forms of lamp holders may be employed inasmuch as the par-, ticular type of lamp holder forms no part of the present invention. The arrangement of the mounting bracket l4 and the manner in which it is adjusted on the lamp holder is described in the copending application of Frank C. De Reamer, Serial No. 393,786, flied Ma 16, 1941, and assigned to the same assignee as the instant application. Each end 01 the lamp is provided with spaced contact pins I. which are seated in the body 01' the lamp holder in engagement with spaced contact members l1 and I1, in the manner shown by Fig. 2. The operating mechanism for the fluorescent lamp includes a starter a portion of the starting switch extends through an opening in the reflector surface 13 so that it is readily accessible upon removal of the lamp it from the holders; Normally, the starter socket i9 and thebase of the lamp holder II are concealed within a lighting fixture of which the reflecting surface l3 forms a part.

The starter socket comprises a body 23 of insulating material such as a molded plastic in one face of which is provided an annular recess 2! for receiving the starter switch l8. Starter switches of the type mentioned are customarily mounted within a'container which is adapted to fit within the recess 2|. For making electrical connection with the starter switch, the socket is provided with receptacle means including a plurality of openings formed in the bottom of the recess and which receive the contact pins provided in the base of the starter housing. These pins are illustrated in Figs. 6 and 9 and will be fully described later.

In the arrangement of the openings in the receptacle means, two diametrically opposed keyhole slots 22 are provided for receiving two of the contact pins of the starting switch while another pair of arcuate slots 23 is located between the keyhole slots 22 for receiving two other pins; The slots 22 and 23 are arranged concentrically, as shown by Fig. 3. Cooperating with the keyhole slots 22 are flexible contact members 24 and 25 which extend partly into the planes of the openings of the keyhole slots for engagement with the starter contact pins. Each contact member is formed of relatively heavy spring material, such as spring bronze, and is provided with -a projecting portion 23 which cooperates with the contact pin and locks it' in position in the narrower portion of the corresponding keyhole slot. At one end, flexible member 24 is bent over to form a terminal porin a recess 40 in the other end of the housing.

tion 21 which rests in grooves 23 in the outerwall of the socket housing and is provided with "a terminal screw 29 for connection to an electrical circuit. The other flexible member 25 is formed with a flat terminal portion 30 which rests in a recess 3| formed in the base of the socket housing; the terminal portion is electrically connected to one of the lamp holder contact members, in any suitable manner, as by the elongated screw 32 which extends from the base of the socket into the base of the lamp holder where it is threaded into a terminal portion 33 forming part of the contact member".

Disposed adjacent the arcuate slots 23 is a second set of flexible contact blades 34 and 35,

each ofwhich extends into the plane of a corresponding slot 23 for engagement with a contact pin on the starter. The contact blades 34 and 35 are made of relatively light spring material, such as phosphor bronze. Contact blade 34 is secured in any suitable manner, as by spot welding, to a terminal plate 33 mounted in spaced grooves 31 in an end wall of the socket housing; the terminal plate is provided with a screw 38 for making an electrical connection therewith. The other flexible blade 35 is likewise provlded with a terminal plate 39 seated The terminal plate 39 is connected in any suitable manner to the other lamp holder contact blade H as, for example, by an elongated screw 4! extending from the bottom of the socket housing to the base of the lamp holder where it is threaded into a terminal portion 42 formed on the other contact member l'l'.

Disposed between the contact blades 34 and 35 is a current conducting member 43 which may take the form of a U-shaped strip, the ends of the U engaging the ends of the flexible blades 34-and 35. This strip rests in a groove (not shown) in the bottom face of the socket housin'g. Normally, the contact blades are spring biased into electrical engagement with the current conducting member 43 except when they are moved away from the member upon engagement with the starter'contact pins as the latter are rotated in the arcuate slots.

The pairs of flexible members move within recesses 44 formed in the bottom face of the housing and they are held in assembled position by a cover plate 45, of any suitable insulating material, such as sheet fiber, which extends over the recesses and is fastened to the base by drive pins 43 secured in openings 41. The cover plate also holds the conducting member 43 in assembled position.

The starter socket thus far described is adapted to support either of the types of starting switches aforementioned and may be used to mount the switches in the lamp operating circuit without any changes in the structural arrangement ofthe elements or in, the wiring of the lamp. The structures of the various starting switches and the manner in which the switches cooperate with the mounting socket will now be described.

In Fig. 6, we have illustrated a starter of the type described in the aforementioned Wels Patent 1,951,112. This starter includes a heater resistance 50 connected by lead lines 5| and 52 ,to contact pins 53 and 54, respectively, which a silver contact. Cooperating with the contact 59 is a like contact 60 mounted on a, relatively rigid contact blade 3| which, in turn, is connected by a lead 62 to still another contact pin 33 mounted in the disk 55. For the purpose of reducing radio interference. a condenser C is connected across the pins 33-and 53, and thus across the contacts 59 and 30. To insure proper mounting of the starting switchin the socket, the contact pins 53 and '33'are provided with enlarged ends which fit into the enlarged portions of the keyhole slots quite readily but which cannot be inserted into thei'arcua'te slots 23.

When a starter of this type is mounted in the socket, the contact pins 53 and 63 are inserted into the larger portions of the keyhole slots and rotated into the narrower portions where they engage the flexible contact members 24 and 25. The pins snap past the projecting portions 26 on the flexible members so that the pins are held locked in seated position. At the same time,

the heads on the pins contact the under side of the base adjacent the narrower-portions I of the slots so" that the starter cannot be pulled out of the socket except by nrst rotating it. 81-

multaneously, the contact pins II and I4 engage the flexible blades 84 and II, respectively, and

blades. By this arrangement, the starter switch h properly connected into the operating circuit of the fluorescent lamp.

I In this ircuit, current from an alternating current supply line 94 flows through a current limiting reactor ii to the contact blade 94, then through the contact pin 93, resistance 99 to the other contact pin I4, contact blade 35, then by a lead line 99 to a left-hand filament 01 of the lamp, leadline 48' to the contact-blade 24, con- ..tact. pin II, to the movable contacts 59 and ill,

and then to the other contact .pin 93, contact blade 25, by a lead line I! to a right-hand fllarnent I9 of the lamp. and thence to another supply lead ll. Since contacts 59 and II are normally closed when current is turned on from the supply lines, it iiows through the path just described giving an immediate heating of the cathodes 61 and I9. Heater resistance It is also in circuit so that heat is generated to bend the bimetallic strip. to open the contacts 59 and 69. The thermal capacity of the strip 56 is such. however, that the contacts are not immediately opened but a time delay occurs, for example, a delay of one totfour seconds, so that current flows through the lamp cathodes for a sufllcient length of time to heat them to a point at which in the starter socket in the manner disclosed by 7 Fig.1!) with thecontact pins 19 and 89 seated in the keyhole slots 22 in engagement with the contactmembers 24 and 2!, respectively; vThe contact blades 34 and 3! remain in electrical engagem at with the current conducting member 43 so that a connection is maintained directly across these blades inthe manner shown by Figs. 10 and 11. In the operation of the starter of Fig. 9, closure of an operating'switch of the 7 current supply causes 'a glow discharge to take place in the evacuated envelope betweenthe electrode 16 and the other bimetallic electrode 15. "This glow discharge causes the bent end of the bimetallic strip 15 to contact the electrode 19, closing the circuit through the switch and stopping the glow discharge. When the circuit closes, current flows from, the supply line 64 through the reactor 95 to the contact blade 34, thence through the current conducting member 43 to the other, contact blade 35, lead line 66, left-hand cathode 91, the other contact member 24, contact pin 80, the closed contacts.|5 and I9, contact pin 19, the other contact member 25, the. right-hand cathode III to the other supply line. II. Since closure of contacts 'I5.and 16 stops the glow discharge, the bimetallic strip cools oil to open the contacts. However, the thermal capacity of the strip is such that a short time interval occurs before the contacts open, for example, an interval of one to four seconds. During this intervaLthe cathodes are heated to an emissive'point so that upon opening of the contacts the reactor provides a surge of currentacross the lamp cathodes, causing a.

glow discharge and lighting thelamp.

they becomeemissive. After the predetermined time delay, the bimetallic strip so is heated sufilciently'toopen the contacts 59. When this occurs, the shunt path through the starter switch across the filaments is broken down so that the reactor 95 provides asurge of current causing a glow discharge to take place between the illaments 8'! and I9, lighting the lamp. Since the heating resistance UII is connected in series with the supply line and lamp the contacts 59 and II are maintained in open position as long as It will be apparent that in the cincuit arrangements of Figs. 8 and 11 the starter socket and the lamp holder are wired into an operating circuit the current supply is turned on.- In this manner, I

it will be manifest that our socket makes provision for connecting a starting switch of the type described directly into the lamp operating circuit simply by plugging theswitch into the socket. Moreover, our starter socket is adapted equally aswell to support starter switches of other types, such as a glow switch starter of the type described in the aforementioned Smitley Patent 2,280,550.

This type of starting glow switch is illustrated by Fig. 9 and comprises a U-shaped bimetallic member]! and a cooperating electrode 16, both of which are enclosedwithin a glass envelope 'l'l'under vacuum. The bimetallic element I5 is connected'by a lead 19 toa contact pin 19 while the electrode II is connected to a similar contact 89 by a lead II. A capacitor C is connected across these elements for the purpose of reducing radio interference. The contact members l9 and II are mounted on an insulating disk ",the same as in the caseo! the starter of Fig. 6 and are provided with enlarged heads so that they may be inserted in the keyhole slots 22 only. It will be noted that the starter of Fig. 9 is provided with only two contact pins whereas the starterot Fig. 6 is provided with four.

The glow switch starter of Fig. 9 is mounted for the lamp in exactly the same way, irrespective of which type of stater is used. Either one of the two types of starters disclosed herein may be inserted in the starter socket and-an appropriate connection is automatically made to the operating circuitby engagement of the starter pins with the corresponding flexible contact members of the socket. I! the heater type starting switchshown by Fig. 6 is employed, the additional contact pins 53 and i4 cooperate with the corresponding contact blades 34 and 35 and move them out of engagement with the current conducting member '43 whereas if the glow switch starter of Fig. 9

is used, the contact blades 34 and 35 areconnected to the current conducting member 43 in a normal manner so that a circuit extends from the reactor directly to one of the lamp holder contacts.

Our socket provides for a considerable savingin manufacturing cost since it is necessary to manuiacture only a single type of socket for both of the aforementioned types of starters now on the market. The arrangement is one in which either type of starter switch may be connected into the lamp operating circuit without making any ex-.

temal changes in the circuit connections to the lamp. While the starter socket H has been illustrated and described as mounted on the base of the lampholder, it should be manifest that it may be mounted separately from the lamp holder by replacing the screws 32 and 4| with appropriate lead wires. 1

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. A socket comprising a base of insulating material having receptacle means in a face thereof, said receptacle means com-prising a plurality of concentrically arranged arcuate slots for receiving the contact pins of an electrical device and flexible contact blades adjacent each slot for engaging a corresponding contact pin, and means I for normally electrically connecting two of said contact blades, the contact pins of the electrical device being adapted to be inserted in said arcuate slots and rotated therein, rotation of the pinstween said keyhole slots, all of said slots 'rbeing L arranged concentrically, contact members cooperating with said keyhole slots, said contact members being provided with projecting means, other contact elements cooperating with said ar-' cuate slots, means for electrically connecting said last-mentioned contact elements, the contact pins'of the electrical device being adapted to be inserted in said slots and rotated therein, the pins in said arcuate slots engaging the last-mentioned contact elements upon rotation to move them out of electrical connection with each other, the contact pins inserted in said keyhole slots being locked therein by engagement with the projecting means on said first-mentioned contact members.

3. In a socket for mounting an electrical device having a plurality of contact pins, a base of insulating material, a pair of opposed keyhole'slots, a pair of opposed arcuate slots located between said keyhole slots, all of said slots being arranged concentrically, contact members cooperating with said keyhole slots, said contact members being provided ,with projecting means, other contact elements cooperating with said arcuate slots, and a current conducting member mounted on said base, the last mentioned contact elements being normally biased into engagement with said conducting member unless some of the contact pins are seated in said arcuate slots to engage said last mentioned contact elements to move them out of engagement with said current conducting member, others of the contact pins being held in locked position in said keyhole slots by the pro- Jecting means on said first-mentioned contact members.

4. In a socket for mounting an electrical device having a plurality of contact pins, a base of insulating material, a pair of opposed keyhole slots, a pair of opposed arcuate slots located between said keyhole slots, all of said slots being arranged concentrically, contact members cooperating with said keyhole slots, other contact elements cooperating with said arcuate slots, means for electrically connecting said last-mentioned contact elements, the contact pins of the electrical device being adapted to be inserted in said slots and rotated therein, the pins in said arcuate slots engaging the last-mentioned contact elements upon rotation to break the electrical connection therebctween, and means -1'or locking the contact pins inserted in said keyhole slots in engzgement with the corresponding contact memrs. l 5. In a socket for mounting an electrical device having a plurality of contact pins, a base of insulating material, a pair 01' opposed keyhole slots, 9, pair of opposedarcuate slots located be-- tween said keyhole slots, all of said slots being arranged concentrically, contact members cooperating with said keyhole slots, other contact elements cooperating with said arcuate slots, and-a current conducting'member mounted on said base, said last-mentioned contact elements being normally biased into electrical engagement with the current conducting member.

6. A socket comprising a base of insulating material having receptacle means in a face thereof,

said receptacle means comprisinga plurality of concentrically arranged elongated slots for receiving the contact pins of an electrical device by rotation therein, flexible contact blades adjacent each slot for engaging a corresponding contact pin, and a current conducting member located between two opposite slots. corresponding o'ppo-- site contact blades being normally biased into engagement with said current conducting member unless engaged by some of the pins and moved out of engagement therewith upon rotation of the pins in said slots.

7. A socket comprising a base of insulating material having receptacle means in a face thereof, said receptacle means comprising a plurality of concentrically arranged elongated slots for receiving the contact pins of an electrical device and movable contact blades adjacent each slot for engaging a corresponding contact pin, two of said contact blades being normally electrically interconnected, the contact pins of the electrical device being adapted to be inserted in said slots and rotated therein, rotation of the pinscausing them to engage said two contact blades to move them-out of electrical connection with each other.

8. A socket comprising a base of insulating material having receptacle means in a face thereof, said receptacle means comprising a plurality 01' concentrically arranged elongated slots for receiving the contact pins of an electrical device and movable contact blades adjacent each slot for engaging a corresponding contact pin, and a current conducting member with which two 01' said contact blades are normally engaged for electrically interconnecting them, the contact pins of the electrical device being adapted to be inserted in said elongated slots and rotated therein, rotation of the pins causing them to engage said two contact blades to move themout of electrical connection with said current conducting member.

ADOLF G. MUELLER. .JOHN M. PISTEY. 

